The invention provides a slide locking guide device which is arranged at a locking station section of a slide and matched with a locking device at the locking station section. The slide locking guide device comprises a locking seat and a locking guide plate, wherein the locking guide plate is arranged on the locking seat and provided with a locking guide slope; the locking guide slope can be propped against a locking swing rod which is located on a locking hook of the locking device and extends outwards, and the locking swing rod moves towards the oblique lower side of a slide running track under the limitation of the locking guide slope and drives the locking hook to hook a locking shaft of the slide simultaneously, so that the locking device on the slide and the locking guide device cooperate with each other to lock the slide automatically, and the working efficiency of the integral coating technology is improved. The invention further provides a slide unlocking guide device and a rotary car body coating conveying system.